Method and Devices for a Sub-Splenius/Supra-Levator Scapulae Surgical Access Technique

ABSTRACT

A novel posterolateral inter-muscular approach has been developed to access the cervical spine. The approach includes elevating the splenius capitis and trapezios muscles dorsally to create a window for deep spine access, wherein the window comprises:
         i) an anterior superior border of the trapezius muscle;   ii) an anterior inferior border of the splenius capitis muscle, and   iii) a posterior superior border of the levator scapulae muscle.       

     Preferably, a device such as an implant or an instrument is then passed through the window to manipulate the spine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/469,912, filed on Mar. 27, 2017. U.S. application Ser. No. 15/469,912is a divisional of U.S. application Ser. No. 13/627,294, filed on Sep.26, 2012 and now issued as U.S. Pat. No. 9,622,779. U.S. applicationSer. No. 13/627,294 claims the benefit of U.S. Appl. No. 61/663,074,filed on Jun. 22, 2012. U.S. application Ser. No. 13/627,294 also claimsthe benefit of U.S. Appl. No. 61/552,433, filed on Oct. 27, 2011. Theentire contents of each of these applications is incorporated herein byreference.

BACKGROUND OF THE INVENTION

Surgical access for superficial structures such as the eye, skin orteeth present little challenge. However, for treatment of pathology deepin the body, the surgical approach may risk violating or potentiallyinjuring several healthy tissues in the process of reaching the surgicaltarget. In addition, an optimal surgical route would not place any vitalstructures at risk when at all possible. Because, however, the spinalcolumn lies deep in the very center of the body, it presents uniquechallenges for surgical access to its pathologic targets.

Posteriorly, spinal surgical access must traverse multiple anatomicplanes and deep layers of muscle. Anteriorly and laterally, besides themuscular impacts, approaches also frequently engage multiple vitalstructures in the passage between the skin and the target. Theseanatomic realities by necessity create a major part of the overall riskand morbidity for the patient, as well as more technical challenges forthe surgeon.

Pathology in the cervical spine is ubiquitous and commonly includesherniated disc, stenosis, disc degeneration, facet disease, tumor,trauma and other instabilities. The majority of cervical problemsrequiring surgery occur between C₂ and T₁, and currently there are twocommon surgical approaches for accessing this region—the anterior andthe midline posterior approaches. See FIG. 10. While both are commonlyutilized, each has significant drawbacks and unique morbidities thatshould ideally be overcome due to their common application.

1. Current Approaches: Description, Advantages and Problems A AnteriorApproach

The patient is positioned supine and the surgical team is standingthroughout the procedure. A three to four centimeter incision is placedeither on the left or right medial boarder of the stemocleidomastoid,with the plane of dissection passing medial to the carotid sheath.Incisions are normally placed transversely and are extended slightlywhen access to more than two vertebral bodies is necessary. A verticalincision is usually utilized when more than 3 vertebral bodies need tobe accessed simultaneously, with this incision being five or morecentimeters in length. By necessity, the carotid sheath must bemobilized laterally and the esophagus, thyroid, trachea, and larynx aremobilized medially. This is mostly an inter-muscular plane of dissectionwith muscular damage being limited to the platysma and the omohyoidsuperficially, and the longus colli deep on the anterior aspect of thespine. Collectively, this amount of muscular disruption is typicallyconsidered relatively insignificant. However, there are several vitalstructures in the route of this dissection. Airway retraction andmanipulation or post-op swelling can lead to post-op airway obstructionwhich can be fatal in rare cases. This has led to many adjustments inretraction and ET cuff management but the potential still exists,particularly in prolonged cases. The carotid artery and internal jugularvein can be injured during the approach or plaques dislodged from thecarotid in older patients potentially resulting in a stroke.Additionally, vocal changes postoperatively can occur due to significantretraction or scarring of the larynx or unintended injury to thelaryngeal nerves, especially the recurrent, which is potentially in theplane of dissection. Furthermore, dysphagia is frequent after thisapproach from swelling, scarring and the required esophageal retraction.This dysphagia often resolves over several months but can be extremelytroublesome for daily function and can result in permanent difficultywith eating and even aspiration. Other important nerve structures atrisk include the sympathetic trunk which lies on the anterior aspect ofthe longus colli (Homer's syndrome) and the hypoglossal nerve if theexposure is extended to C4 or above. The superior, middle and inferiorthyroid arteries and veins are directly in the field of approach andmust be controlled as well, representing one of the other potentialcauses of rare but life threatening post op airway obstruction fromhematoma.

Once the spine is reached, the surgeon has excellent access to the disc.However, it becomes necessary to remove the entire anterior longitudinalligament and the disk structure itself in order to reach the typicalpathologies at the posterior aspect of the disc space, as well asgaining access to the spinal canal and the nerve roots in the foramen.Consequently, when decompressions of the spinal cord or nerve roots isrequired from an anterior approach, some type of motion segmentreconstruction is usually mandated due to the subsequent loss of motionsegment integrity that is required through this route. This means thatvirtually every standard anterior cervical approach results in some typeof arthroplasty or fusion to reconstruct the loss of motion sectionintegrity that may be entirely secondary to the approach (even if fusionwas not indicated by the patient's original pathology). Anterior discwithout fusion was done in the 1960s-70s but now have been abandoned.This is in sharp contrast to current treatment the lumbar spine wheresurgeons commonly perform posterior decompressive procedures without anyfusion or reconstruction, since that anatomic route of approach does notcreate enough disruption to mandate some type of reconstruction as anaftermath. Besides increasing the need for fusion, the anterior cervicalapproach also presents another challenge in that if nerve compression islocated laterally, the exposure will be limited by the uncovertebraljoint, and more significantly, the vertebral artery. Injury to thisvital structure can occur with dissection in the foraminal area or ifreconstruction deviates off the midline. Vertebral artery injury canpotentially be catastrophic.

The anterior cervical exposure usually requires self-retainingretractors, which can occasionally injure the esophagus or thesympathetic trunk if they migrate out of position. For this reason anassistant is often required to stabilize retractors in their position,and assistance is also often necessary in accessing the contra lateralside of the exposure and in maintaining orientation to the midlineduring reconstruction. Typically this exposure can be extended up to C₃and down to C₇ or T₁ depending on the position of the clavicle. Evenwith nasotracheal intubation, the mandible can occasionally obstructclear access to the upper cervical area. When revision is required afterthe anterior cervical approach, access is often done on thecontra-lateral side due to major challenges with scaring around all thevital structures on the side of prior approach, making revision on theipsilateral repeat dissection potentially risky.

Only pathology in the anterior aspect of the spine and the anteromedialforaminal region can be visualized through this approach.

Primary advantages to this approach are universal surgeon familiarity,quick and easy dissection for the surgical team, very limited muscledamage, and minimal post-operative surgical pain with quick return tofunction for the uncomplicated patient.

Primary problems associated with the approach include putting severalvital structures at risk in the approach route, potential for rare butcatastrophic complications, dysphasia, limited foraminal access, andalmost always requires extensive reconstruction or fusion.

B. Posterior Midline Approach:

The patient is positioned prone with the surgical team standingthroughout the procedure. The main difference versus the anteriorapproach is that there are virtually no vital structures at risk in thissurgical route, but extensive muscle detachment, dissection, anddisruption is mandatory. This approach utilizes amidline verticalincision and requires detachment of all three layers of cervicalmusculature. The superficial, intermediate, and deep layers are alldetached and dissected from the tip of the spinous process down acrossthe deep surface of the lamina to the lateral aspect of the lateralmass. This involves detachment of the longissimus, spinalis, trapezius,semi spinalis, splenius, multifidus, rotators and rhomboid at C7.Because of the bulk and depth of these combined posterior cervicalmuscles, the dissection usually extends at least 1 level above and belowthe target level just to gain adequate access at the ends of therequired field. This can create risk of damage to healthy motionsegments. Although this is a “subperiostial” exposure, all of thesemuscles are detached, and exposure of the lateral mass usually disruptsthe dorsal ramus at the dissected levels either directly or through theposition of the deep retractors. Self-retaining retractors (Cerebellaror other) are required, and these by necessity exert significantpressure on the muscle structures due to the depth and bulk of theseposterior cervical muscles. This retractor pressure can result in ischemic necrosis of the muscle tissue bilaterally. Additionally, themidline ligamentous structures (ligamentum nuchae and the interspinousligaments) are usually detached, which disrupts the integrity of theentire posterior musculo-ligamentous system in the cervical spine.Additionally, as these muscular structures span multiple segments, thiscervical posterior exposure can potentially impact muscular andligamentous function far beyond the extent of the approach, by injuringstructures that span from the occiput to the upper thoracic region.

Once the deep cervical spine is exposed, the surgeon has good access tothe dorsal elements and the spinal canal. Midline laminectomy or otherdissection can be done as well as foraminal dissection. The limits ofthe thick muscular retraction laterally create some restriction for farlateral exposure. The working angle that the surgeon has providesexcellent opportunity for placing lateral mass instrumentation, butcreates significant challenges for placing cervical pedicle screws wherethe converging angle of the instrumentation is at odds with the thicklateral musculature. Access to antero-lateral pathology such asherniated disc can be accomplished although there are limitations towhat can be done on the floor of the spinal canal due to considerationsof spinal cord safety. It is noteworthy that the structures bestaccessed through this approach are the spinous processes, while in factvirtually no significant pathologies are recognized in this midlinearea.

As is seen in the lumbar spine (and in contrast to the anterior cervicalapproach), posterior cervical access often does not require a fusion,and lends itself to decompressive laminectomy or forminotomy procedureswithout fusion or reconstruction when appropriate. This approach hasalso been expanded to include laminoplasty although post op muscularpain and stiffness has been a problem Closure of this multi-muscularincision requires multiple deep layers and is sometimes challenging bothcosmetically as well as in achieving excellent re-approximation of eachanatomic level.

Problems associated with this approach include extensive deep muscularand ligamentus disruption, difficult bilateral retraction, significantoften prolong post-operative incisional pain, difficult convergenceangle to pedicles and referred pain from injury of soft tissuestructures.

Advantages of this approach include surgeon familiarity, no vitalstructures in the surgical route, no catastrophic potential approachcomplications and finally, it does not demand fusion as an aftermath inmany situations.

Approach-Related Prior Art

The literature suggests that there are substantial problems andpotentially disproportionate problems related to the anterior approach.Although the anterior approach is quite commonly used, popular andwidely accepted, there are obviously ongoing issues that need to beaddressed. A survey of the activity in the literature would suggest thatperhaps the posterior approach has either created less difficulties orat least garnered less attention with respect to potentialcomplications. While recognizing that both approaches have importantclinical utility, their deficiencies do suggest a need for improvementand perhaps indicate a rationale to look into the posterior surgicalapproach options that seem to have a better safety profile with lesspotential for catastrophe. There will always be some needs for both, asthe surgical approach must “go where the pathology is” but we may beable to improve the safety profile of many cases.

While the typical posterior approach has been almost universallyutilized via the midline, there have been exceptions that have allowedfor creation of postero-lateral or lateral cervical approaches that willbe outlined below, although none of them mimic in any way the procedurethat we have described.

In 2009 B. Zhao, Spinal Journal 9:822-829 2009 described aposterolateral exposure for excision of extra foraminal tumors. However,this utilizes a traditional midline incision and a standard medial tolateral exposure out to the lateral mass, detaching all the muscles in astandard approach. Further extension of their dissection is then takenby detaching the Levator scapulae and the scalene muscles to provideaccess to the brachial plexus and anterior structures. Thus, the planeof dissection is exactly opposite to that which we are utilizing, andour approach intentionally spares the muscles they are detachingspecifically for the purpose of protecting the brachial plexus. It wouldbe theoretically possible, to convert our exposure to an extensileapproach that would allow access to the brachial plexus and the lateralcervical spine or even anterior cervical structures. This extensileapplication would no longer be considered “inter-muscular” or in any wayminimally invasive or tissue sparing, although it certainly may haveutility in unusual pathologic circumstances.

S. J. Hyun Surgical Neurology 72:409-13, 2009 described anotherposterolateral approach which is based on the posterior aspect of thestemocleidomastoid. This surgical approach mobilizes the V-2 segment ofthe vertebral artery for access to the lateral cervical area and isparticularly targeted to the very upper cervical spine. This approachdoes not engage in any way the plane of dissection on the posterolateralcervical spine as we have described, and remains anterior to theScalenes.

Upper cervical and high cranio cervical posterior or far lateralapproaches have been described for pathology involving the foramenmagnum, clivus, and the C1-C4 region.

Although these approaches do place the skin incision on the lateralcervical area, all of these techniques involved detachment of thesplenius, semispinalis, and even the longissimus from the skull (K A.Tsutsumi et al Neurological Surgery 23:301-09 1995; X. G. Tong ChineseJournal of Contemporary Neurology and Neurosurgery 8:38-42 2008).Therefore, all of these craniocervical and far posterolateralpre-cervical approaches are muscle detaching and radically differentfrom our muscle sparing technique. Additionally, the posterolateralupper cervical approaches discussed above also involve lateralpositioning of the patient, with the surgical team typically standingwhich are in sharp distinction to our technique. The plastic surgeryliterature includes descriptions of multiple flaps in the cervical areautilizing the superficial and intermediate layers for reconstruction. Asplenius Capitis flap and others for reconstruction of pathologies suchas Amold-Chiari malformation have been described (Elshay et al N. I.Elshay Plastic and Reconstructive Surgery 9 3:1082-86 1994). These ofcourse involve detachment and mobilization of muscular structures andare in no way an

inter-muscular approach for cavity creation such as we have outlined.Tunneling techniques and pocket creating techniques have been widelyutilized in plastic surgical strategies in the areas of the chest andthe abdominal wall for various reconstructive applications althoughthese have not been used with respect to surgery on the spinalstructures themselves.

The importance of the superficial and intermediate cervical musculaturethat we are preserving by this new technique has been suggested inmultiple areas of the literature.

Panjabi et al estimated that 80% of stability of the cervical spine ismuscular, with only 20% being osteoligamentous in nature (ClinicalBiomechanics 1998). A 2011 study by E. Okada et al, EuroSpine Journalpublished online Mar. 23, 2011 Springer, with MRI evaluation showed aclear age dependent atrophy of the splenius and semispinalis which arethe largest of the posterior muscles in the cervical spine. This wasseen throughout all cervical levels, and highlights the criticalimportance of preserving as much of this muscle function as possibleparticularly in the middle-aged and older patients. All of the keycervical muscles described by M. S. Conley et al Spine 20: 2505-12 1995for extension (semispinalis and splenius) and as well as for rotation(splenius, semispinalis, Levator scapuli and scalene) are all preservedby the approach that we have outlined.

A detailed anatomic study by A Ono et al Spine 33:349-54 2008demonstrated wide variations in anatomic insertion patterns of cervicalmusculature. This includes the splenius, serratus, and rhomboid. Thiswork stresses the need to preserve tendinous attachments to the variousand contiguous posterior midline structures, and emphasizes theunpredictable clinical impact of detaching these muscles from theirmidline insertions as is done in today's standard approaches. All of theNuchal based musculature was felt to be critical to craniocervicalfunction through the analysis of this study.

A N. Vasavada et al Spine 23:412-22 1998 reported that the largestmoment arms throughout the head and neck system are generated by thesemi spinalis and splenius capitis in extension, and by the trapezius inaxial rotation. This type of work further emphasizes the criticalimportance of preserving midline honey attachments of these superficialand intermediate muscular layers which is in sharp contrast to what iscurrently done with the standard posterior cervical exposures. Themechanical importance of the splenius muscle is further illustrated bytreatments that have been described for splenius type torticollis. Insuch cases, approaches to the upper splenius and semispinalis have beendescribed for the purpose of selective dennervation. This approachinvolves a midline based dissection with intentional sectioning of themotor branches, which is in sharp contrast to our approach whichinvolves the approach plane from a lateral direction specificallypreserving these motor branches as much as possible.

There is additional prior art with respect to elevating type retractorsystems. These have been utilized primarily in the fields of plasticsurgery and general surgery. The Laprolift system was described foraccess to the retro peritoneal space and the abdominal cavity. Itsutilization was extended to be an adjunct to access to the anterioraspect of the lumbar spine. To our knowledge, there is no an artsuggesting cavity creation technique or technologies for the posterioraspect to the spine such as we have described.

SUMMARY OF THE INVENTION

A novel postero-lateral, inter-muscular approach has been developed toaccess this commonly pathologic occiput-thoracic cervical region, morepreferably C2-T1. See FIG. 11. While the description that followsspecifically involves the cervical spine, many of the approach elementscan be transferred to other spinal approaches.

A novel triangular surgical approach window is now described, locatedthrough the confluence of three prominent cervical muscles. Nowreferring to FIGS. 9A-9C, the triangle is described by;

a) the anterior superior border of the trapezius muscle;

b) the anterior inferior border of the splenius capitus muscle, and

c) the posterior superior border of the levator scapulae muscle.

Palpitation of the trapezius and the triangle is possible and bluntdissection can lead directly to the spine. No major superficial orintermediate muscle attachments or fibers are affected, and the approachfollows a natural intermuscular and intemervous plane to the lateralmass. The elevation of the splenius and trapezius dorsally creates andopens a potential space for deep spine access. The spinal accessorynerve is safe anteriorlly and laterally. The deep cervical arterybranches are ligated with a bipolar instrument in a conventional manner,and the vertebral artery is safe anterior to the approach, protected inthe foramen tranversarium. All major nerve roots are protectedanteriorly in the Scalene complex. The dorsal Rami are only affected atthe exposed levels similar to a posterior approach. The deep muscularlayers multifide rotators are dissected as needed for honey exposure.The natural intermuscular plane extends from C2 to T1 but can beextended even further. Unilateral foraminal root compression and centralcanal stenosis can be addressed with aunilateral approach, e.g.,unilateral laminectomy or modified unilateral laminectomy allowingpartial removal or thinning of the lamina under the spinous process.Additionally, this surgical approach lends itself to kyphoticdeformities where removing the interspinous ligament and lagamentumflavums allows for restoration of lordosis and fusion of the facet andspinous processes. Laminoplasty can be easily accessed with thebilateral approach. Reconstruction options would include spinousprocess, posterior or lateral aspect of the lateral mass, facet orpedicle fixation. The facet complex can be viewed laterally, permittingunique access for facet decompressions, fusion, reconstruction andinstrumentation. This exposure avoids all the major muscle dissection ofthe traditional midline approach, and for MIS considerations it allowsfor a contiguous surgical field unlike the current application ofmultiple tubes/ports. Unlike current MIS tube inset techniques, thisapproach spares the trapezius, spenius, levator, spinalis, and most ofsemispinalis capitis.

Accessing the cervical spine through this sub-splenius window alsoenables anew type of retractor for the support of the internal workingchamber during surgery. A tent can be made by dorsally elevating themuscle fibers on the roof of the windowed opening. A lighted button isdisclosed as the preferred device for making this tent, but other typesof retractors can be used. New access instruments are provided forclearing and dissecting this space such as a reverse dog-bone Cobb andmodular angled instruments.

The sub-splenius access also leads to new implant designs that arelateral specific or unilateral.

DESCRIPTION OF THE FIGURES

FIG. 1 discloses a retraction instrument of the present invention.

FIG. 2 discloses a retractor component of the present invention.

FIG. 3 discloses a retraction instrument of the present invention havinga light source and battery.

FIG. 4 discloses a retraction instrument of the present invention havinga convex outer surface and a concave inner surface.

FIG. 5 discloses a retractor component of the present invention having aflexible outer nm.

FIGS. 6a-6f discloses retractor components of various shapes.

FIG. 7, Sa and Sb disclose retraction instruments in which a wing ismated to the retractor.

FIG. 8c discloses a wing of the retraction instrument.

FIG. 9 discloses a plate having an outer rim and an interior region 73,wherein the interior region of the plate defines a plane, wherein theouter rim of the plate extends out of the plane of the plate.

FIGS. 9A-9C disclose views of the access region of the present invention

FIG. 10 discloses the trajectories of conventional approaches to thecervical spine.

FIG. 11 discloses the trajectories of approaches to the cervical spineproviding by the present invention.

FIGS. 12a-12m discloses a number of different embodiments involving theretractor of the present invention with additional performance-enhancingfeatures attached thereto.

FIGS. 13a-13p discloses a number of different embodiments involving theretractor of the present invention with additional support featuresattached thereto.

FIGS. 14-33 disclose an apparatus of the present invention involved inmaking a working cavity.

FIGS. 34a-c discloses articulating instruments that can be used incarrying out the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment of the present invention, there is provided a surgicalprocedure comprising the steps of:

a) moving (preferably by lifting) the splenius capitus and trapeziusmuscles dorsally to create a window for deep spine access, wherein thewindow is defined by:

-   -   i) an anterior superior border of the trapezius muscle;    -   ii) an anterior inferior border of the splenius capitis muscle,        and    -   iii) a posterior superior border of the levator scapulae muscle.

b) passing a device through the window, and

c) manipulating the spine with the device.

This procedure provides the surgeon with a minimally invasive method ofaccessing the cervical spine via a posteriorlateral corridor thatproduces very little trauma because it takes novel advantage of a tissueplane between these muscles unilateral or bilateral. Accordingly, thesuperficial and intermediate layers of the cervical spine are completelyavoided while the deep layers of the cervical spine bear only minimaldisruption.

Because the above-mentioned window is adjacent the cervical spine, insome embodiments, manipulation of the spine is carried out between thesecond cervical and first thoracic vertebra, possibly T2.

In some embodiment, the spinal manipulation is carried out with aninstrument such as a retractor. The retractor can be used to increasethe access window made by moving the splenius capitis and trapeziusmuscles dorsally.

In some preferred embodiments, the retractor comprises a plate connectedto a needle by a suture. Once this retractor has been passed into thewindow, the needle is passed outward through the trapezius and spleniusmuscle and through the skin of the patient. The needle is then pulledaway from the skin to make the suture taut and thereby retract the skinof the patient away from a selected tissue of the patient and create anoperative space there between.

In other embodiments, the device that passes through the window can bean implant. In some embodiments, the implant is selected from the groupconsisting of a screw, a cervical plate, a fusion cage and a motion discrod, facet or lateral mass clamp.

In some embodiments, the procedure further comprises the step ofremoving a flavum selected from the group consisting of the interspinousflavum and the ligamentum flavum.

Removing a flavum allows for access to the spinal canal, anddecompression or correcting lordosis.

In some embodiments, the procedure further comprises the step ofmanipulating a facet joint complex through the window. Common proceduresinvolving the facet joint that can be carried out through this procedureinclude arthrodesis partial distraction, facetectomy, and reduction ofdislocation, transfacet fixation, and tumor removal.

In some embodiments, the step of moving the targeted muscles compriseselevating the muscles with a balloon, table-based retractor.

Due to the novel posterolateral angle of approach provided by thepresent invention, the surgeon may perform the tissue plane dissectionfrom a sitting position. Thereafter, the surgeon may be able to carryout subsequent steps, such as manipulating the spine, from the samesitting position.

In some embodiments, the tissue plane dissection step comprises the stepof releasing a deep fascia between the splenius and levator scapulaemuscles. This may be accomplished by digital dissection, scissors, andharmonic tools.

In some embodiments, the tissue plane dissection step comprises the stepof releasing insertions of multifidi and some portion of semispinalisfrom the dorsal lateral mass, laminae and spinous process bases,proceeding from lateral to medial. This may be accomplished by Cobbelavator, harmonic or other energy tool such as a bovie. In someembodiments thereof, the released multifidus, along with the splenius,are lifted upwards dorsally to maintain the operative space. This dorsalupward lifting of the multifidus may be carried out by aretractor andunder illumination from a light inside the patient.

Typically, the splenius capitis and trapezius muscles are accessedposterolaterally.

In some embodiments, there is provided a surgical procedure comprisingthe steps of:

a) dissecting the inter-muscular plane anterior to the splenius muscleto create a window, and

b) passing a device through the window.

In some embodiments, there is provided a surgical procedure comprisingthe steps sequential of:

a) dissecting a sub-splenius capitis/supra-levator scapulae tissue planeto create a window,

b) passing a device through the window,

c) manipulating the spine with the device, and

d) retracting one of the splenius captious and the levator scapulae tocreate an expanded window which forms the opening of a cave.

Preferably, the step of retracting is performed with a plate having anouter surface, wherein the outer surface bears against one of thesplenius captious and the levator scapulae. Also preferably, the step ofretracting is performed by pulling the plate via the needle and suturemethod discussed above in one or multiple vectors.

In some embodiments, this procedure further comprises the step ofirradiating the window with light from a light source in order toimprove the visibility of the surgeon in the deep spine region.Preferably, the light source can be located in the window to provide ahigh level of brightness upon the spinal area. In some embodiments, thelight source is attached to the retraction plate and may also includecamera tracking devices.

In some embodiments, there is provided a surgical procedure comprisingthe sequential steps of:

a) passing a retraction instrument inward through an incision in theskin of the patient to a location adjacent a selected tissue, whereinthe retraction instrument comprises a plate connected to a needle by asuture,

b) passing the needle outward through the skin of the patient;

c) pulling the needle away from the skin to tension the suture andthereby retract the skin of the patient away from the selected tissue.

In some embodiments, there is provided a surgical procedure comprisingthe steps of:

a) dissecting an inter-tissue plane defined by a first tissue and asecond tissue to create a window,

b) inserting a retractor into the window,

c) pulling the retractor in the direction of the first tissue

Preferably, the step of pulling retracts only the first tissue andcreates an expanded window. The present inventors have recognized thatboth sides of the window need not be retracted—that assymetric allyretracting the window will be sufficient and reduce tissue trauma.

Preferably, the first and second tissues are muscles, such as thesplenius capitis and levator scapulae muscles. These are the musclesthat define the initial approach window.

In some embodiments, the step of pulling causes the outer surface of theplate to bear against the first tissue. This differs from theconventional means of retraction in which the tissue are pushed insteadof pulled. In some embodiments, the step of pulling is accomplished bymagnetic attraction. In others, the step of pulling is accomplished bypulling a ligament attached to the retractor. In still others, the stepof pulling is accomplished by suction. After this retraction, theprocedure typically further comprises the step of: manipulating thespine of the patient through the window.

In its broadest sense, and now referring to FIG. 1, the preferredmedical retraction instrument of the present invention comprises aretractor 1 connected to a needle 3 by a suture 5.

In some embodiments, the needle has a distal end portion 7 that iscurved. This curve advantageously provides ease of insertion point and adorsal ward direction. In some embodiments, substantially the entireneedle is curved.

In preferred embodiments, the retractor is in the form of a plate 9 andhas a width W, a length L and a thickness T, wherein the thickness issubstantially less than each of the width and length. Providing aplate-like geometry to the retractor allows it to accomplish its purposeof retracting one tissue away from another while at the same time nottaking up unnecessary space.

Because the location of the window is deep within the spine areas, itwould be helpful to light this area so that the surgeon can haveimproved visibility. Therefore, in some embodiments, the surgicalinstrument passing through the window comprises alight with or withoutcamera.

In some embodiments, and now referring to FIGS. 3 and 4, the retractorhas an inner surface 11 and a convex outer surface 13, wherein thesuture 5 extends from the outer surface and wherein the instrumentfurther comprises a light source 15 connected to the inner surface. Theprovision of the light source on the inner surface allows the light toshine upon the spinal region.

In some embodiments, the inner surface 11 of the retractor plate is madeof a reflective surface in order to better disperse the light emitted bythe light source upon the window.

In some embodiments, the light source comprises an LED. Because LEDs areavailable in small sizes but provide high intensity light, LEDsconstitute a preferred method of lighting. The light source furthercomprises a battery 17 connected to the LED, thereby eliminating anyelectrical wires from the design that may clutter up the operatingtheatre.

In other embodiments, however, the suture 5 may be adapted to transmitlight to the inner surface of the component. This embodiment allows forthe desired lighting while providing for an inexpensive instrumentdesign.

In some preferred embodiments, the outer surface 13 is convex. Thisconvexity allows the retractor to form a tent of the window border,thereby increasing surgeon visibility into the spinal area.

In some embodiments, and now referring to FIG. 5, the retractor has anouter rim 19 and an interior region 21, wherein the outer rim comprisesa flexible material. The flexible material allows more physiologic edgeloading of muscle tissue.

In some embodiments, and now referring to FIG. 6a-6f , the width andlength of the retractor define an area selected from the groupconsisting of a substantially circular area; a substantially oval area;a star-shaped area; a substantially triangular area; a substantiallyrectangular area and a kidney bean area. The oval area is a preferredembodiment because it better fits the elongated opening typically madeby the incision. A kidney bean shape may be used to clear the spinusprocess.

Typically, the retractor defines an area of between about 4 cm² to about16 cm².

In some embodiments, and now referring to FIG. 7, the retractor has anouter rim and an interior, wherein the outer rim comprises a firstmating feature 23. This mating feature may be connected to a secondmating feature 25 on a second component 27, such as a wing. The wing orextension provides for extra retraction area with a minimum of addedbulk and ability to extend or reduce field of retraction withoutrepositioning the suture.

In some embodiments, the retraction plate comprises a polymer. If theplate is made substantially from a polymer, its cost may be soinsubstantial that it may be deemed a one-use disposable.

In some preferred embodiments, and now referring to FIGS. 8a-8c , thereis provided a medical retraction instrument comprising:

a) a plate 31 having an inner surface 33 and outer surface 35 and a pairof throughholes 37,

b) a suture 41 having first 43 and second 45 ends,

c) first and second needles 47,

d) an elongated wing 49 having a distal head 51, a shaft 53 and aproximal end portion 55,

wherein the suture passes through the first throughhole in a firstdirection and through the second through is an opposite direction,

wherein the first needle is connected to the first end of the suture,

wherein the second needle is connected to the second end of the suture,and

wherein the distal head of the elongated wing is passed through thefirst throughhole.

In some embodiments, the distal head of the elongated wing contacts theinner surface of the plate. This allows the head to swivel to adjustableand fixed angles.

In some embodiments, the proximal end portion of the elongated wing hasa throughhole 57. This throughhole can be used to add further wings tosupporting sutures.

In some embodiments, the shaft widens from the distal head to theproximal end portion. The widening of the shaft allows for broadermuscle retraction.

In some embodiments, each throughhole of the plate defines an inner rim59 of the plate, wherein each inner rim has a recess 61. Preferably, therecesses of the inner rims oppose each other, thereby providing theelongated wings with an easy securement from either left or right(superior/inferior) directions. In some embodiments, there are multiplerecesses or teeth with matching features on the wings that provide anangular adjustment and securement of the elongated wings.

In some embodiments, the shaft of the elongated wing extends from theouter surface of the plate. Because it extends from the outer surface ofthe plate, the wing provides an extended level of retraction in thedirections needed as the surgery progresses from level to level.

In some embodiments, the shaft of the elongated wing defines alongitudinal axis A and the distal head is off-axis. The off-axis natureof the distal head provides a flip in connection that keeps thetissue-facing portion in line with the originally placed button.

In some embodiments, the shaft has an outer surface 63 and the distalhead has an outer surface 65, and the outer surface of the shaft issubstantially parallel to the outer surface of the distal head. There isadvantage in this condition in that the edges of the field aresymmetrically posted when needed.

In some embodiments, the first throughhole has a diameter, wherein theshaft of the elongated wing defines a longitudinal axis A, and thedistal head of the elongated wing has a length LH in the direction ofthe longitudinal axis, and wherein the length of the distal head isgreater than the diameter of the first throughhole. When the length ofthe distal head is greater than the diameter of the first throughhole,the flip in connection is not permitted to pass back through thethrough-hole as long as the loads on the wing are in the direction awayfrom the tissue.

In some embodiments, the distal head has an outer surface 65, and theouter surface of the distal head of the elongated wing is substantiallyparallel to the inner surface of the plate. In this condition, thetissue-facing portion stays in line with the originally-placed button.This continues if additional wings are attached in chain-like fashion tothe wing recesses 57.

When the proximal end portion 55 of the elongated wing component iscurved, the wing advantageously traverses an offset to retract tissuethat is not directly in line with the originally placed button.

In some embodiments and now referring to FIG. 9, the plate 71 has anouter rim 75 and an interior region 73, wherein the interior region ofthe plate defines a plane, wherein the outer rim of the plate extendsout of the plane of the plate. When the outer rim of the plate extendsout of the plane of the plate, this advantageously fixates the plate inthe tissue and provides for distributing the loads on the tissue. Atransition zone at the extents of the plate can be used to soften ortighten the grip on the tissue.

Also in accordance with the present invention, there is provided amagnetic comprising:

a) a ferromagnetic plate having an inner surface and an outer surface,

b) a light source attached to the inner surface of the plate,

This magnetic retractor can be placed within the window and then coupledacross the patient's skin with a second magnet. The second magnet canthen be pulled to lift the skin and thereby create an expanded window.Preferably, the outer surface of the plate comprises a ferromagneticmaterial.

In some embodiments, the ferromagnetic material is either iron or a rareearth. Avoids requirement for passage of needle while allowing quickconnect—disconnect for adjustment.

In some embodiments, the method steps of the present invention may beundertaken manually by a surgeon. In other embodiments, these methodsteps are undertaken robotically. In others, the method steps areundertaken by a mixture of manual steps and robotic steps.

The methods of the present invention are intended to be carried outbroadly in the occiput-thoracic cervical region. Preferably the methodsof the present invention are intended to be carried out broadly in theC2-T1. T2 is potentially accessible via the upper thoracic region. Aboveabout C2, more injury would be contemplated.

In some embodiments, a lapascope may be used to provide the positivepressure and the insufflation necessary to retract tissue.

Further, it is believed that the unilateral laminectomy with spinousprocess fixation that can be achieved through this approach has acomparable biomechanical stability to uniulateral lateral mass screwsand unilateral pedicle screw fixation. It also approaches the stabilityprovided by bilateral lateral mass screw fixation, which is consideredto be the standard of care today.

(FIG. 12)

Now referring to FIGS. 12a-12m , there are provided a number ofdifferent embodiments involving the retractor of the present inventionwith additional performance-enhancing features attached thereto.

In FIG. 12a , the retractor 101 is provided with a light emitting device103. This diode can increase the surgeon's visibility of the workingenvironment with the cavity. In FIG. 12b , the retractor 101 is providedwith a telescopic extension 104 that slides outwards to extend the reachof the retractor, thereby widening the footprint of the cavity. In FIG.12c , the retractor 101 is provided with a number of irrigation andsuction options, including an irrigation tube 105 having an irrigationport 107, and a suction tube 106 having a suction port 108. Theseoptions allow the surgeon to use irrigation fluid within the cavity,thereby assisting in cleaning the cavity of loose tissue. In FIG. 12d ,the retractor 101 is provided with supporting legs 109 that hold openthe cavity made by the retractor. This enhances or stabilizes the volumeof the cavity. In FIG. 12e , the retractor 101 is connected to a suture110 that passes through the patient's skin 102. When the suture istensioned from outside the patient, it enhances or stabilizes the volumeof the cavity. In FIG. 12f , the retractor 101 is radiolucent and isprovided with a radiopaque marker 111 that allows the retractor to belocated on an x-ray. In FIG. 12g , the retractor 101 is provided withboth a suture 110 and a fiberoptic cable 112. Light emitted through thefiberoptic cable can increase the surgeon's visibility of the workingenvironment with the cavity. In FIG. 12h , the retractor 101 is providedwith alight-emitting coating 113, such as a phosphorescent (glow-in-thedark) coating. In FIG. 12i , the retractor 101 is provided with aneuromonitoring feature 114 (such as an electrode) connected to anelectrical cable 115. The electrode can help the surgeon detect nervoustissue in the vicinity of the cavity. In FIG. 12j , the retractor 101 isprovided with temperature/pressure controls, such as sensor 116 (whichcan be either a temperature or pressure sensor) connected to anelectrical cable 115. A pressure sensor can help the surgeon determinewhether the retractor is imparting an unsuitably high pressure or stressupon the tissue surrounding the cavity. In FIG. 12k , the retractor 101is provided with a strain gauge sensor 117 for measuring tension,wherein the sensor is connected to a suture 110 and an electrical cable115. In FIG. 12l , the retractor 101 is provided with spring scale 118for measuring force, wherein the spring scale is connected to a suture110. In FIG. 12m , the retractor 101 is provided with an anti-infectivecoating 119. This coating helps prevent bacteria from moving from theretractor to the patient's tissue, thereby preventing infections.

Now referring to FIGS. 13a-13m , there are provided a number ofdifferent embodiments involving the retractor of the present inventionwith additional support features attached thereto.

In FIG. 13a , the retractor 101 is provided with support from inside thecavity by a C-shaped clip 120. In FIG. 13b , the retractor 101 isprovided with support from inside the cavity by a gear/rack typetelescopic arch 121. In FIG. 13c , the retractor 101 is provided withsupport from inside the cavity by a jack-type telescopic column 122. InFIG. 13d , the retractor 101 is provided with support from inside thecavity by an inflatable arch 123 (providing tent-like support). In FIG.13e , the retractor 101 is provided with support from inside the cavityby a circumferential spring sheet 124. In FIG. 13f , the retractor 101is provided with support from inside the cavity by a dual rack retractorblade assembly 125. In FIG. 13g , the retractor 101 is provided withsupport from inside the cavity coil spring 126. In FIG. 13h , theretractor 101 is provided with support from inside the cavity by amemory metal-based spring 127 (made of, for example, nitinol). In FIG.13i , the retractor 101 is provided with support from inside the cavityby coil springs 129 connected by abeam 128. In FIG. 13j , the retractor101 is provided with support from inside the cavity by folding legs 130connected by a beam 128. In FIG. 13j , the metallic retractor 101 holdsthe cavity open via attraction to a magnet 131 located outside thepatient. In FIG. 13l , the cavity is held open with tension from outsidethe patient (via suture 110) and with a wall type anchor having two legsdisposed inside the cavity. The anchor comprises a threaded anchorportion 125 and a folding anchor linkage 126. In FIG. 13m , the cavityis held open with tension from outside the patient (via suture 110) andwith a wall type anchor having a single leg disposed inside the cavity.The anchor 127 comprises a toggle leg 128. In FIG. 13n , the cavity isheld open with tension from outside the patient (via suture 110) throughthe use of adhesive tape 129. In FIG. 130, the retractor 101 is providedwith support from inside the cavity by a telescopic tube 130 a securedby a set screw 103 b. The tube portions are slid apart and then held inplace. In FIG. 13p , the retractor 101 is provided with support frominside the cavity by cervical retractor-type device 131.

Example I

The patient is positioned prone, but the surgeon is comfortably sitting.This approach can be unilateral or bilateral, normally for access up toC₂-T₁. A longitudinal skin incision

is based on the lateral boarder of the Trapezius, preferably in therange of 20-30 mm long and radiographically localized if needed. Thesuperficial fascia is opened (20-85 mm or more) preferably with Metzalong the lateral Trapezius boarder in the rage of (30-35 mm). TheLevator scapulae is digitally identified laterally, and the deep fasciaopened between the Splenius and Levator scapulae muscle. This plane canbe opened bluntly with finger dissection or with metz from 10 mm (up to150 mm) as needed. The Spinal Accessory nerve is safe, restinganteriorly and laterally on the anterior boarder of Levator Scapulae,and is not retracted or involved in the approach. Blunt digitaldissection is directed straight medially and quickly identifies thelateral mass and the dorso-lateral corner of the facet joint.Confirmation of desired spinal level is done under direct or assistedvisualization, palpation (e.g. finger sensing) and radiographic ally.

Up to this point only limited unilateral fascial release has beenrequired and no muscle origins or insertions have been disturbed. Thesuperficial and Intermediate cervical muscular layers and ligamentousstructures remain intact dorsally. The extent of release of thesuperficial and deep facia is governed by the number of vertebral levelsto be accessed much like an anterior cervical approach. Once theanatomic level is confirmed, dissection is taken cephalad and candallyonly over the levels needed. A contiguous unilateral field of exposurefrom C₂ to T₁ can be obtained. Unlike tubular MIS approach systems, thisapproach provides a fully continuous surgical field at the target. Theinsertions of multifidi are released form/dissected off the dorsallateral mass, laminae and spinous process bases proceeding from lateralto medial. The facet capsules can be spared or removed as indicated. TheNuchal, interspinous and supraspinous ligaments are preserved, as wellas ligamentum flavum, and all major muscle groups. Once released, themultifidus, along with the splenius, semispinalis and trapezius arelifted upwards dorsally with either standard or special retractors withor without illumination port to maintain the operative space. Theretraction is not a typical opposed bidirectional system, but has asingle multidirectional vector which puts no pressure on anteriorstructures. Complete posterior honey exposure can extend unilaterallyfrom the spinus process base medially across the lamina and facet to thelateral surface of the lateral mass. This entire dissection is all doneunilaterally and many pathologies could be addressed without disturbingthe contralateral tissues. If indicated, the entire spinius process andinterspinious space can be accessed laterally by dissecting thespinalis. If needed, bilateral exposure can be accomplished through amatching skin incision on the other side, and the left and rightsurgical fields could be connected across the midline. Closure requires1-2 sutures in the deep fascia, 2-3 sutures in the superficial fasciaand a subcuticular skin closure. There is no muscle or ligamentousreattachment required. It is possible that this dissection would allowsame day discharge.

No major superficial or intermediate muscle attachments are affected,and the approach follows a natural intermuscular and internervous planeto the lateral mass. The anatomic elevation of the splenius andtrapezius dorsally creates and opens a natural potential space ventralto the muscles for deep spine access. The spinal accessory nerve is safeanteriorly and laterally. The small deep cervical artery branchesrunning on the lateral lamina would be bipolared in usual fashion forposterior approach, and no significant vascular structures lie alongthis path between C2 and T2. If one crossed above to the C1 lamina thevertebral artery at C 1 could be accessed. In this described approach toC2-T2, the vertebral artery is safe anterior to the approach, protectedin the foramen transversarium. All major nerve roots are protectedanteriorly in the Scalene complex, and not subject to retraction. Thedorsal rami are only affected at the exposed level(s) similar to aposterior approach, although fewer levels would need to be exposed forthe same pathology. Unilateral foraminal nerve root compression andcentral canal stenosis as well as posterior ligament ossifications canbe addressed with a unilateral approach, e.g. unilaterallaminectomy/facetectomy or modified unilateral laminectomy with internallaminoplasty allowing partial removal or thinning of the lamina underthe spinous process centrally. Additionally, this surgical approachlends itself to kyphotic deformities were removing the interspinous andLigamentum Flavums allows for restoration of lordosis and fusion of thefacets & spinous processes. Laminoplasty can be easily accessed with thebilateral approach. Far lateral dissection anterior to the lateral masscould provide access to the post foraminal roots and plexus if needed.Reconstructive options would include spinous process, lateral mass, orpedicle fixation. The facet complex can be viewed laterally permittingunique access for facet decompression, as well as fusion,reconstructions and instrumentation if needed

FIG. 14 of the disclosure shows an operative window opening O being heldopen by a device of the present invention during surgery. The skin hasbeen incised to create the opening O, a chandelier-type retractor (notshown in FIG. 14) has been inserted through the opening below the tissueto be retracted, and a punch 205 with attached suture 110 is being usedto lift the chandelier (and thereby the tissue) to create a workingcavity.

One embodiment of the procedure of the present invention is as follows:

Following the preparation of the operative window via incision and bluntdissection, a surgeon loads the correct size chandelier-type retractor203 onto a channel 118 in the distal portion 204 of the holder 201 asshown in FIGS. 17 and 18. The Chandelier-type retractor 203 is theninserted into the operative window opening O, as shown in FIG. 15.

As shown in FIG. 19, the punch 205 and the punch sled 207 are plungedproximally-to-distally so that the punch point 209 makes a definitiveconnection with the chandelier 203. This is shown in cross-section inFIGS. 25 thru 27. This connection is both mechanical and electrical.

After the connection to the chandelier 203 is made, the punch 205 andpunch sled 207 are pulled distally to proximally, leaving a trailingamount of the suture 110, as shown in FIG. 16 and FIG. 20. This is shownin cross-section in FIGS. 28 thru 30. The suture 110 is allowed to trailbehind due to the excess suture available, pre-packed or wound withinthe punch 205, as shown in FIG. 31. The suture 110 reaches a limitinglength so that the punch 205 can be used to tension the chandelier 203.

After the punch sled 207 has returned to its original proximal position,the punch and punch sled can be disconnected from the holder 201, andthe distal portion of the holder can be removed from the window, asshown in FIG. 17. The holder can then be manipulated by an operatingroom attendant or it can be parked upon a frame that supports the holderat the correct vector above the operating window. The frame can be fixedto the surgical bed on a rail or post arm or can be fixed to anyoperating room stand, hook, or pole.

The chandelier 203 may have a light. The lighted portion of thechandelier may be actuated by battery connection. As shown in FIG. 24,the chandelier consists of a bi-polar receptacle 210 at its center withcircuitry leading to LED lamps 211. The point 209 of the punch 205 has atwo-conductor geometry similar to a common head phonejack as shown inFIG. 27. The plus and minus wires 221 from the batteries 223 (FIGS. 31and 32) are incorporated into the suture 110 (FIG. 32) and connectedrespectively to each of the conductor poles. As the chandelierconnection is made, the battery power travels through the receptacle andthe chandelier lights turn on. In one preferred embodiment, thebatteries are stored within the punch. However, the batteries can alsobe sealed within the chandelier and turned on with a switch or byremoving a sterile insulating strip between the batteries. In thismanner, the suture would not need to incorporate electrical wiring—itwould need only support the retraction forces.

The methods of the present invention may find utility in the followingsurgical procedures:

1. Cervical laminectomy: used for cervical stenosis (congenital andacquired), cervical spondylotic myelopathy, multilevel spondyloticradiculopathy, ossification of the posterior longitudinal ligament(OPLL), ossification of the yellow ligament (OYL), neoplasm, andinfection. MIS unilateral decompression using laminectomy and posteriorcervical stabilization and fusion can be achieved using either:

-   -   a) Pedicle screws/rods fixation    -   b) Spinous process screws/rods or plate fixation    -   c) Translaminar plates/screws fixation    -   d) Lateral screws/rods fixation    -   e) Facet screws    -   f) Bilateral laminectomy/Laminoplasty

2. Single level foraminotomy for radiculopathy (including unilateralforaminotomy and unilateral facetectomy);

3. Posterior element tumor resection;

4. Brachial Plexus Surgery;

5. ORIF Cervical Fracture; and

6. Posterior Cervical Fixation (traditional lateral masscranio-thoracic).

The natural lordotic curvature of the cervical spine distributes thecompressive load differently than in other spinal locations. Thecervical spine transmits 36% of compressive loads through the anteriorcolumn, while 64% is borne through the posterior column facet joints.(Beck D McAllister, Brandon J Rebholz, Jeffery C Wang; Is posteriorfusion necessary with laminectomy in the cervical spine? SurgicalNeurology International Spin, E, Surg Neural Int 2012, 3: 225) In orderto preserve stability, the surgeon needs to recognize the potentialdestabilizing impact of a posterior approach as laminectomy, facetectomy(medial, partial, or full) may contribute to instability/deformity. Whenperforming cervical laminectomies, the extent of facetectomy performedover single or multiple levels helps to determine the development ofinstability. If it is necessary to perform multiple foraminotomies, orresect greater than 30-50% of the facet joint, it is recommend theaddition of a posterior cervical fusion to avoid iatrogenic instability.(Beck D McAllister, Brandon J Rebholz, Jeffery C Wang; Is posteriorfusion necessary with laminectomy in the cervical spine? SurgicalNeurology International Spine, E, Surg Neurol Int 2012, 3: 225).

Unilateral foraminal nerve root compression (radiculopathy) can beaddressed with a unilateral foraminotomy and central canal stenosisand/or posterior ligament ossifications (PLL) causing myelopathy canalso be addressed by a multilevel unilateral laminectomy with or withoutpartial removal or thinning of the lamina under the spinous processcentrally and stabilization with unilateral facet screw fixation,laminoplasty plates/screws, pedicle or lateral mass screw/rod fixationor even spinous process screws/rod or plate fixation.

Additionally, this surgical approach lends itself to kyphoticdeformities were removing the interspinous and Ligamentum Flavums allowsfor restoration of lordosis and fusion of the facets and/or spinousprocesses and fixation using facet screws, lateral mass screws/rods orpedicle screws/rods or spinous process anchors with rods or plates. Thistechnique also can be used to augment the stability of multilevelanterior cervical fusion.

Unilateral laminectomy and laminoplasty can be easily accessed with thebilateral approach. Far lateral dissection anterior to the lateral masscould provide access to the post foraminal roots and plexus if needed.Reconstructive options would include laminoplasty screws/plates, spinousprocess, lateral mass, or pedicle fixation. The facet complex can beviewed laterally permitting unique access for facet decompression, aswell as fusion, reconstructions and instrumentation if needed.

Some challenges associated with this approach include an unfamiliarorientation for dissection, dorsal ramus dissection, limited access toanterior floor of spinal canal, and the need for some articulatedinstruments. Now referring to FIGS. 34a-c , there are providedarticulating instruments that can be used in carrying out the presentinvention. The working tips of these instruments can be a driver 301, anawl 302 and a drill 303.

There are numerous advantages associated with this approach. Forexample, this exposure avoids all major muscle dissection of thetraditional posterior midline approach, and for MIS considerations itallows for a contiguous surgical field unlike the current application ofmultiple tubes/ports. No vital structures are presented in route, andthere appear to be no catastrophic potential risks as exist withanterior approach. The approach is, relatively quick and may be carriedout from a comfortable sitting position for operating team providingergonomic improvement for the surgeon. The approach, often only beneeded unilaterally to preserve function.

1.-90. (canceled)
 91. A surgical method, comprising: forming an incisionin the skin of a patient to access the spine; passing a retractorthrough the incision to increase an access window to the spine; passinga distal portion of an articulating instrument through the window; andperforming a foraminotomy using the articulating instrument; wherein thedistal portion of the articulating instrument is angled relative to aproximal portion of the instrument.
 92. The method of claim 91, whereinthe articulating instrument is a drill.
 93. The method of claim 91,further comprising irradiating the window with light from a lightsource.
 94. The method of claim 91, further comprising capturing animage of the window with a camera.
 95. The method of claim 91, whereinthe incision is formed in the posteriolateral corridor.
 96. The methodof claim 91, wherein at least one step of the method is performed by asurgical robot.
 97. The method of claim 91, further comprising detectingnervous tissue in the vicinity of the window using an electrode.
 98. Themethod of claim 91, further comprising inserting an implant through thewindow.
 99. The method of claim 98, wherein the implant is a fusioncage.
 100. The method of claim 91, further comprising providing at leastone of irrigation and suction through the window.